1. Field of the Invention
This invention relates to improvements in bulk storage and handling systems and particularly to such systems that utilize a flexible inflatable membrane silo liner which inflates under low pressure to gently nudge material past its angle of repose and/or into a discharge cavity.
2. Background Art
Although material handling and storage bins such as silos have been known and widely used almost since the dawn of civilization, there is little art on such bins with flexible membrane fluid-assisted discharge. Such art as is known to Applicant has been cited in commonly owned U.S. Pat. No. 4,421,250, issued Dec. 20, 1983 and U.S. Pat. No. 4,449,646, issued May 22, 1984, and U.S. patent application Ser. No. 357,589, filed Mar. 12, 1982 and Ser. No. 357,592 filed Mar. 12, 1982 as well as PCT International application publication No. WO82/03839.
The most relevant of this background art appears to be U.K. patent No. 1,144,162 published March 1969 which shows a silo with a single flexible liner inflated from the bottom, and U.S. Pat. No. 3,941,258 to Ide which discloses a bulk storage and unloading apparatus having sidewalls and a liner with inflatable bladders between the sidewalls and liner.
In connection with the actual construction and installation of such silos using a flexible membrane discharge of the type disclosed in the above-identified prior applications, a number of problems have surfaced. These problems include incomplete discharge of materials by the bin, discharge blockage by the membrane, improper membrane positioning during deflation, membrane damage due to improper loading techniques (user related problems), and membrane damage due to excessive pressure buildup.
There remains a need in the art for improvements in flexible-membrane materials-handling bins which overcome the problems associated with their use.